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Management of Fever Flashcards Preview

What is fever?

A normal response to various circumstances - usually due to viral or bacterial infection.A controlled physiologic response where the core temperature of the body temperature is increased and new balance of heat loss and production is establishedIt's a defence system; the body's immune response to pyrogens

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What are the 6 methods of taking body temperature?

RectalEarOralForeheadAxillaryTranscutaneous

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What defines a fever?

Generally defined as rectal temperature over 38ºCThe degree of the child's fever may correlate the likelihood of a serious bacterial infectionGenerally self-limiting (3 days)

What is considered above normal temperature?

What is the recommended technique for measuring temperature from birth to two years?

1. Rectal2. AxillaryTympanic is not recommended

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What is the recommended technique for measuring temperature from 2 to 5 years old?

1. Rectal2. Axillary, tympanic

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What is the recommended technique for measuring temperature for children older than 5?

1. Oral2. Axillary, tympanic

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What are some practical points for measuring temperature?

Do not use an oral thermometer for rectal purposes and vice versaA digital thermometer may be used for either oral or rectal (plastic sheaths are available)Digital is preferred - convenience (safer, faster, easier) and cost (cheaper in the long run)Fever strips (transcutaneous method) no longer recommended - not an accurate reading

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Describe the pathophysiology of a fever

Fever is produced by pyrogens of either endogenous or exogenous originsProstaglandins of E2 series are produced in response to the circulating pyrogens and elevate the thermoregulatory set point in the hypothalamusWithin hours, the body temperature increases the new set point and fever occursBody temperature is increased by vasoconstriction of peripheral blood vessels, shivering to increase heat production, behavioural changes

What are endogenous pyrogens?

What are exogenous pyrogens?

Chemicals produced by bacteria or by components of the organism. Stimulate the release of endogenous pyrogens

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What controls the body's temperature?

Hypothalamus is the body's thermoregulatory centre - balancing heat production/dissipationFever is controlled by the hypothalamus which increases body temperature when exposed to pyrogens (increased production of prostaglandins)

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What is hyperthermia?

An increase in body temperature not due to the hypothalamus (i.e., physical exertion)

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What are risk factors?

When should a patient be referred?

Babies under 6 monthsFever lasting over 72 hours (with out without treatment)Fever lasting over 24 hours without obvious causeFever over 40.5ºCChild appears very ill, is excessively cranky or irritable, cries inconsolablyPatient has persistent wheezing and coughPatient has rash with fever (could be life threatening)Patient is difficult to arouse, confused or delirious, has recently received chemotherapy or has serious underlying diseasePatient had recent surgery or dental procedures, recently travelled or eaten raw or poorly cooked meat/fish or recently started a new drug (associated with hypersensitivity)Child has any other symptoms that bothers the parents

Should a fever be treated pharmacologically?

There are arguments against treating a fever (it's part of the body's defence mechanism)The decision to use antipyretics must be individualizedThe main reason to treat a fever is the patient discomfort associated with fever

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What is fever phobia?

Unrealistic concerns and misconceptions that can result in heightened anxiety and inappropriate treatment of fever

Can acetaminophen and ibuprofen be used for a fever?

They are the the only therapeutic choices for managing a fever in children

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What is the goal of pharmacological treatment of a fever?

Reduction of the hypothalamic set pointDo not lower "normal" body temperatureRegular/short term use of agents is recommended - intermittent use may cause 'swings' in temps (increased metabolic demand)

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What is the MOA of acetaminophen?

Acetaminophen reduces fever by inhibiting the formulation and release of prostaglandins in the CNS and by inhibition endogenous pyrogens and the hypothalamic thermoregulator centreIt's a safe and effective analgesic and antipyretic that causes a 1-2ºC decrease in temperature

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What is the onset, time to peak, duration of acetaminophen?

Oral: 30 minutesPR: slowly and incompletely absorbed Time to peak: 3 hoursDuration: 4-6 hoursIt is extensively metabolized by the liverIt is rapidly and completely absorbed from the GI tract

What is the pediatric dosing for acetaminophen?

How safe is acetaminophen?

Generally, considered a safe analgesicRelatively safe for short term use in children, pregnancy and lactationDosing adjustment may be necessary for patients with renal dysfunction but not in the elderly

What are the drug interactions of ibuprofen?

It can reduce ASA's anti platelet effectIt can increase the risk of GI pain/ulceration when taken with alcohol and/or corticosteroidsAntihypertensive agents (the antihypertensive effect is inhibited, possible hyperkalemia)Increase the risk of bleeding with anticoagulantsIncrease the risk of nephrotoxicity with cyclosporineIt can increase the levels of lithium and/or methotrexate

What is the MOA of ASA?

Inhibits the COX enzyme in the periphery and CNS

What is the OOA and DOA of ASA?

Onset: Within an hourTime to peak: 3 hoursDuration: 4-6 hours

Can be ASA be used in children?

Not recommended in children. Avoid in children less than 18 years old who have a viral illness (due to Reye's syndrome). The cause of fever is often unknown, therefore avoid ASA in children

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What is Reye's syndrome?

Rapidly progressive encephalopathy with cerebral oedema, hepatic dysfunction and metabolic derangements which begins several days after apparent recovery from a viral illness (especially varicella or influenza A or B)Characterized by vomiting and confusion, quickly evolving to seizures and comaSalicylate use identified as a major precipitating factor

What are signs of ASA overdose?

Is ASA safe in pregnancy/breastfeeding?

Risk in first and third trimester (compatible at low doses)Potential toxicity in breastfeeding

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What is ASA-induced asthma?

30 minutes to 3 hours post ingestion of ASA, it's possible to observe clinical syndrome characterized by the onset of asthmaIt's common in 5-20% of asthmatics with concomitant allergic rhinitis or nasal polypsProsposed mechansim: decrease in prostaglandins results in an increase in leukotrienes (important mediator in asthma and allergies)

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What is the MOA of naproxen?

Same as ibuprofenFor adults only

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What is the dosing for naproxen for adults 12-65 years?

1 tab (220 mg) q8-12hMax 2 tabs in a 24 hour period

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What is the dosing for naproxen for adults over 65 years?

q12hMax 2 tabs in a 24 hour period

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What is the OOA of naproxen?

Unknown for fever (20 minutes for analgesic effects)

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Is naproxen safe to take in pregnancy/breastfeeding?

Pregnancy risk factor CNot recommended for breastfeeding

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Describe renal tolerability of NSAIDs

Prostaglandins (PGs) are important for maintenance of renal blood flow and tubular transport of electrolytes. Increased PG release occurs to compensate for an increased level of angiotensin II and norepinephrineNSAIDs inhibit this compensatory mechanism therefore they can lead to:-renal and systemic vascular resistance-increased BP-worsening of pre-existing CHFNSAIDs therefore often interfere with the effects of antihypertensive agents

Should products for treatment of fever be alternated or combined?

It is not recommended due to safety issues with this practise-risk of overdose-medication errors due to complexity regimen-increased side effects

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What is considered first line for treatment of fever?

Consider acetaminophen first line therapy in:-ASA-sensitive asthma-gastritis or PUD-increased risk of bleeding-patients with renal dysfunction-CV or hypertensive patients-multiple concurrent therapy-pregnant or breastfeeding (especially third trimester)

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What are monitoring parameters?

Watch for the development of rash or allergic reactionsSide effects (GI intolerances, tinnitus)Monitor patients with pre-existing co-morbid conditions (CHF, CV or pulmonary insufficiencies)Improvement should be seen within 24-72 hoursTreatment should not be used for more than 3 days without referral to determine underlying causeComfort is the goalMonitor for dehydration and seizures in children at risk